Optical fibers and methods of fabrication

Abstract

An apparatus and method for fabricating an optical fiber, an optical fiber preform, and an optical fiber core rod are disclosed herein. In particular, the process of fabricating an optical fiber preform involves, during a modified chemical vapor deposition process, collapsing the substrate tube into an optical fiber preform, and compressing the optical fiber preform in the longitudinal direction. An optical fiber preform that is shorter, but larger in diameter is thus formed. The optical fiber preforms therefore can be stacked during the optical fiber fabrication process, which is useful in drawing longer optical fibers with comparable outer diameter and core diameter to that used as the industry standard.

1 . A process for fabricating an optical fiber core rod, comprising: 
 providing a glass substrate tube with a longitudinal axis;    depositing materials within the glass substrate tube via a vapor deposition process;    collapsing the substrate tube into an optical fiber preform;    monitoring the diameter of the preform; and    providing compressive movements along the longitudinal axis of the preform when a variation in desired diameter is detected.    
     
     
         2 . The process of  claim 1 , wherein the vapor deposition process includes traversing a heat source along the longitudinal axis of the optical fiber preform to provide heated regions; and 
 wherein the compressive movements along the longitudinal axis of the optical fiber preform are provided while the heat source traverses the preform.    
     
     
         3 . The process of  claim 1 , wherein the compressive movements along the longitudinal axis of the optical fiber preform induce an increase in the core diameter of the preform.  
     
     
         4 . The process of  claim 1 , wherein the compressive movements along the longitudinal axis of the optical fiber preform are applied continuously while a heat source traverses the entire length of the preform.  
     
     
         5 . The process of  claim 1 , wherein the fabricated preform has an outer diameter from approximately 20 millimeters to approximately 54 millimeters.  
     
     
         6 . The process of  claim 1 , further comprising: 
 subsequent to compressing the optical fiber preform, inserting one or more of the preforms into an overcladding tube and collapsing the overcladding tube onto the preform, the cladded preform having sufficient material for producing from approximately 1200 to approximately 3000 kilometers of continuous optical fiber.    
     
     
         7 . The method of  claim 6 , wherein inserting the preform into an overcladding tube further comprises stacking multiple preforms into the overcladding tube.  
     
     
         8 . The process of  claim 7 , wherein the stacked optical fiber preforms are capable of producing an optical fiber with a core diameter of approximately 8 microns.  
     
     
         9 . The process of  claim 6 , further comprising: 
 drawing an optical fiber from the one or more preforms, wherein the optical fiber is from approximately 1200 to approximately 3000 kilometers in length.    
     
     
         10 . The process of  claim 9 , wherein the optical fiber produced has an outer diameter of approximately 125 microns and a core diameter of approximately 8 microns.  
     
     
         11 . The process of  claim 1 , wherein the optical fiber preform has an outer diameter of approximately 150 millimeters.  
     
     
         12 . An optical fiber preform, wherein the optical fiber preform is capable of being stacked in an overcladding tube, thereby producing an overclad preform, having sufficient material for producing approximately 2400 to approximately 3000 kilometers of optical fiber.  
     
     
         13 . The optical fiber preforms of  claim 12 , wherein the stacked optical fiber preforms are capable of producing an optical fiber that has a uniform core diameter profile.  
     
     
         14 . The optical fiber preform of  claim 12 , wherein the stacked optical fiber preforms are formed from a glass substrate tube using a modified chemical vapor deposition.  
     
     
         15 . A control system comprising: 
 a monitor that monitors at least one of core diameter and profile of an optical fiber preform; and    a controller that compares at least one of the core diameter and profile of the preform with at least one of a predetermined core diameter and profile, and determines pressure that should be applied to the preform.    
     
     
         16 . The control system of  claim 15 , wherein the controller is a central processing unit (CPU).